The proposed research is designed to determine how lignin peroxidases degrade a wide variety of recalcitrant environmental pollutants. The research is based upon two hypotheses. One is that lignin peroxidases have high redox potential (are highly oxidizing) in part because they are active at low pH. Secondly, the enzymes can use free radical intermediates to catalyze either oxidations or reductions. It might even catalyze the oxidation of chemicals by the hydroxyl radical by generating superoxide and using metals for a superoxide-driven Haber-Weiss reaction. These hypotheses will be tested by 1, analyzing the peroxidase reactions while varying pH of the concentration of electron donors, acceptors and mediators such as veratryl alcohol; 2, determining which chemicals can be oxidized or reduced; and 3, studying the effects of metals (Mn, Fe and Cu) on the production of hydroxyl radical under conditions where the enzymes produce superoxide.